Persistent high risk human papillomavirus (HPV) infection is a significant cause of anogenital cancers in HIV- positive individuals. The long-term goal of this study is to understand how HPV interacts with one of the same host receptors as HIV and to find new ways to treat HPV infection and associated diseases by activating innate immunity at mucosal surfaces. Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor found in mucosal fluids of the genital tract and has been shown to inhibit infection of macrophages by HIV by blocking the interaction of HIV with annexin A2 (ANXA2). One of the mechanisms by which HPV escapes immunity is inducing tolerance via antigen presentation in the absence of co-stimulation by Langerhans cells (LC), the antigen-presenting cells at the site of HPV and HIV infection. Our unpublished data suggest that the L2 capsid protein of HPV may mediate immune escape by interacting with ANXA2 on LC, thereby suppressing the maturation of LC. LC are also the initial cellular targets of HIV and play a critical role in viral dissemination. Therefore we will explore the relationship between HIV, HPV, ANXA2, and SLPI in LC in this proposal. Our published data show that it is possible to activate HPV-exposed LC with Toll-like receptor (TLR) agonists. However, it is unknown whether TLR agonists will be potent enough to overcome the suppressive effects of HPV-exposed LC from HPV and HIV co-infected individuals. We hypothesize that 1) to escape T cell immunity, HPV16 L2 suppresses the maturation of LC through interaction with the cell surface receptor ANXA2, and 2) that treatment with TLR agonists will increase SLPI production and simultaneously induce HPV-exposed LC to activate HPV-specific T-cells from HPV/HIV co-infected patients. The following aims will be explored: Aim 1) Determine whether HPV16 L2 is responsible for suppressing the maturation of LC through interaction with ANXA2 and assess whether SLPI can block uptake of HPV and HIV by LC;Aim 2) Investigate whether TLR agonists up-regulate SLPI production by LC and induce HPV16- exposed LC to activate HPV16-specific T cells from patients infected with HPV or co-infected with HPV/HIV;and Aim 3) Determine whether apart from HPV16, other oncogenic HPV types also suppress LC maturation, and whether treatment of LC with TLR agonists reverses the immune escape of other high risk HPV genotypes that can cause cancer in HIV-infected individuals. These aims will be accomplished by performing co- immunoprecipitations and knock-down studies in LC to identify the HPV receptor. Reversal of immune suppression will be tested using immune-modulating compounds and immunosuppressive capacity of other HPV genotypes will be assessed by analyzing LC phenotype and function. This mechanistic research could lead to the identification of novel immune modulators with the goal of clearing persistent HPV infection in HIV- infected individuals and therefore reducing risk of developing more serious disease such as cervical, anal and other HPV-associated cancers. PUBLIC HEALTH RELEVANCE: Human papillomavirus (HPV) causes an increased incidence of several different types of cancer in HIV- infected individuals because of their immune suppression. With increased life expectancies due to advances in AIDS therapies and with high incidence of HPV co-infection, there is an urgent need to develop therapeutic strategies to reduce the risk and prevent the development of HPV-associated malignancies. Successful completion of this project will lead to a greater understanding of how HIV and HPV might co-interact with immune cells and the development of strategies to expedite HPV viral clearance in HIV-infected people by activating local innate immunity.